//------------------------------------------------------------------------------
//  <copyright file="PathTrackingAgent.cs" company="Microsoft Corporation">
// The MIT License (MIT)
// 
// Copyright (c) 2014, Microsoft Corporation
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
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//  copies of the Software, and to permit persons to whom the Software is
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// The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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//------------------------------------------------------------------------------

namespace Microsoft.Robotics.Navigation.Runtime.Motion
{
    using System;
    using System.Collections;
    using System.Collections.Generic;
    using System.Linq;
    using System.Runtime.Serialization;
    using Microsoft.Robotics.Hardware.DAC;
    using Microsoft.Robotics.Interaction.Runtime.Input;
    using Microsoft.Robotics.Navigation.Localization;
    using Microsoft.Robotics.Navigation.Motion;
    using Microsoft.Robotics.Navigation.Runtime;
    using Microsoft.Robotics.Navigation.Runtime.Localization;
    using Microsoft.Robotics.Navigation.Runtime.Motion;
    using Microsoft.Robotics.Numerics;
    using Microsoft.Robotics.Runtime;

    /// <summary>
    /// Agent that consumes a path plan and posts drive directions.
    /// </summary>
    [DataContract]
    public class PathTrackingAgent : ConsumerProducerAgent<SimpleAgentMessage<PathPlan>, SimpleAgentMessage<DriveDirection>>
    {
        /// <summary>
        /// Maximum distance (in meters) per drive command.
        /// </summary>
        [DataMember(Name = "MaxDistancePerDriveCommand")]
        private readonly double maxDistancePerDriveCommand;

        /// <summary>
        /// Number of map cell steps ahead to target.
        /// </summary>
        [DataMember(Name = "TargetMapCellsAhead")]
        private readonly int targetMapCellsAhead;

        /// <summary>
        /// Initializes a new instance of the PathTrackingAgent class.
        /// </summary>
        /// <param name="name">Agent name</param>
        /// <param name="planner">Name of agent producing path plan messages.</param>
        /// <param name="maxDistancePerDriveCommand">Maximum distance (in meters) per drive command.</param>
        /// <param name="mapResolution">Map resolution in meters.</param>
        /// <param name="trackAheadInMeters">Track ahead distance (in meters).</param>
        public PathTrackingAgent(string name, IProducer<SimpleAgentMessage<PathPlan>> planner, double maxDistancePerDriveCommand, double mapResolution, double trackAheadInMeters)
            : base(name, planner.Name)
        {
            this.maxDistancePerDriveCommand = maxDistancePerDriveCommand;
            this.targetMapCellsAhead = (int)(trackAheadInMeters / mapResolution + 0.5);
        }

        /// <summary>
        /// Called when the agent receives a message
        /// </summary>
        /// <param name="message">The received message</param>
        public override void Receive(SimpleAgentMessage<PathPlan> message)
        {
            if (message.State.Path == null || message.State.Path.Count() == 0)
            {
                // stop in place
                this.Publisher.Post(new SimpleAgentMessage<DriveDirection>(DriveDirection.Stop, message));
            }
            else
            {
                // track path
                Point2D<int> location = PathPlanningCommon.PosePoint(message.State.CurrentPose);
                DriveDirection direction = PathPlanningCommon.Track(location, message.State, this.maxDistancePerDriveCommand, this.targetMapCellsAhead);
                this.Publisher.Post(new SimpleAgentMessage<DriveDirection>(direction, message));
            }
        }
    }
}
